What Windows can teach the Mac about the switch to ARM processors


We knew ARM-based Mac processors were coming, but Mark Gurman is reporting at Bloomberg that Apple will announce the transition at its online-only WWDC later this month. Back in April, I called on Apple to announce as early as possible and to provide as much detail as possible to both developers and users.

The main thrust of that piece was taking a brief look at the potential pitfalls of the transition. The biggest one is how Apple will handle apps coded for Intel’s x86 processors. The going assumption is that there will be some sort of emulation, but as John Gruber noted yesterday Apple went with a more technically complicated fix for its last processor transition.

As it so often has over the past decade, Windows offers a roadmap of where things could go awry for the Mac. Windows on ARM still has unacceptable compromises for most users when it comes to software compatibility and expectations. I say this as a person who walked into those compromises eyes wide open, buying a Surface Pro X. I essentially use it as a glorified Chromebook and it’s very good at being that thing, but there’s no way Apple would want that for its Mac users.

Speaking of things Apple wouldn’t want: ARM-based Windows computers are slower. Unless you’re able to stay within those Chromebook-esque constraints, things get real chuggy real fast. We’ve all been assuming that Apple’s much-vaunted prowess at making fast ARM chips for iPads will translate well to Macs, but there’s no guarantee that’s true until we get to test them ourselves.

Another thing I’ve learned is that using a Windows computer with an ARM processor actually requires a higher level of technical expertise, because you need to know what won’t work and why going in.

Basically, 32-bit Windows apps can be emulated in ARM, but more modern 64-bit apps cannot. And short of Googling (or, uh, Binging) around for a decent chunk of time, it’s difficult to know if an app you need will work.

That’s surely something Apple will want to avoid, but some kind of technical gotcha may simply be unavoidable — so clear and direct communication will be essential. Apple is less practiced than it used to be at admitting that its products aren’t perfect when it announces them. I’ll be watching closely to see how it handles these issues at WWDC — especially since it’ll be online-only.

Yet another thing we can take away from Windows is the idea that ARM and Intel versions can co-exist. It’s within the realm of possibility that Apple intends to support both x86 and ARM based Mac for the foreseeable future instead of just managing a transition. Gurman’s report, however, says that “the company plans to eventually transition the entire Mac lineup to its ARM-based processors, including the priciest desktop computers.”

Windows is sticking to a plan to support both x86 and ARM (though there may be some secret plan to sunset x86 someday, who knows?). When ARM-based laptops and tablets started getting released, the message was “Here’s a cool new thing you can get if you want, but the reliable old thing isn’t going anywhere.” That’s the Windows way.

If Apple were to take that tack, it would mean a sigh of relief for everybody who needs to buy a Mac for the next year or three.

But it would also mean another potential pitfall. Windows on ARM simply isn’t getting the developer attention and support that standard Windows gets, both within Microsoft and outside it. It was the same with many of Microsoft’s other Windows gambits — simply witness how many times it has rebooted its app framework strategy.

Apple, too, has more than one bet on the table when it comes to developing apps for the Mac. Without getting too deep into the weeds, there are lots of different ways Apple could go. It could limit ARM Mac to iPad-like Catalyst apps. It could try to offer emulation for any app that expects an Intel processor. It could offer a relatively easy transition for developers using existing APIs. It could sunset some APIs while beefing up newer ones like Swift. It could do a lot of different things.

Steven Sinofsky has a long Twitter thread getting into some of the potential issues facing developers depending on what choices Apple makes. He knows of what he speaks when it comes to the difficulties of transitioning a platform to a new processor architecture.

If Apple goes the Windows route and declares that it has no plans to sunset x86 support, then it needs to ensure that both ARM and x86 Macs feel equally supported. If it goes the classic route and declares that the future of the Mac is on ARM, then it needs to assuage concerns that every Mac in existence right now will become obsolete before its time.

Neither path is easy.